She maybe looking for a surogate daddy - The thing about her working two jobs was almost like an hint that she wants saving from her hardship.
It is the power of Puss* at play here in this thread - We know that hooking up with this girl and having a relationship, will lead to you being the daddy of someone elses genetic seed.
I'd only advice men who know there way around women and have built up the hidden A-hole - to date single mums - why? because the latter will give you the power to walk away when the sex drys up. Most AFC will be further ensnared by the puss* to walk -
Next thing you know, she is asking you to move in - she drops one of her jobs to spend time with the kid - You go out to work and find a good % of your wage cut in half looking after someone elses genetic pool. Usually they trap 'nice guys' by getting pregnent or in the very least offer them sex and keep it good until they have the claws in you -
Why any man would knowingly walk into a thing with a single mum is behond me - I'd do it, but then I can walk away very easily - The fact of the matter is, I dont think any guy who is asking the question you posed is in a position to walk away from this girl after she spreads the legs, if anything I can predict your future with 89% certainty, and here it is:
Your so ingrained into getting Puss*, that no advice will be listened to on this forum or any other place - You want that puss* and it's on a plate.
This girl knowing your a nice guy, will entice you with that puss* and in 5 years time, you will be shacked up with her and working like a dog to look after some other mans genetic gene pool - if your lucky you may have a kid of your own in that mix (I say lucky but what I mean is, at least you will have some genetic investment for yourself).
All I am saying is, it takes a strong man to walk away from his emotional and pyhsical desires and drives - it takes a stronger man even more so to walk away from a women who offers him puss*, especcially if originally that guy would ignore glaring red flags to tap it.
This girl would be great if you'd met her in a bar, but she is connected to you - If you sleep with her and dont relationship her, I doubt you'll hear the end of it - and I suspect your not the type of guy to walk away once she has you hooked in.
The only time i'd ever advice anyone to date a women with kids, is if the guy has kids also from another partner.
I've had sex with many, many women and almost all want something more - Unless she is a bar, party girl, then you can walk away never see her again.
This girl is a friend of your sisters, not only will that add pressure, imagine the shi* flinging your sister will do also - Trust me on this, women stick together, she will be more concerned about her friend more then she will be for you, if you think you can just go in and pump and dump!